[chii]

> call that function at compilation time

that's why it's called a macro and not a function. You're using the word function in the mathematical sense, and not in the lisp sense.

[kazinator]

The irrefutable fact is that the author presents the core logic of the file-reading solution as a defn, not a defmacro. It may be driven by a macro, but evidently that part is not noteworthy enough to be presented.

[KingMob]

I mean, sorta, but Lisp macro writers learn early on that macros are also functions, it's just they operate on a list of symbols, and are called in a different phase.

So saying "it can't be a function" doesn't ring true, either.